A vaccine against Marburg virus would be highly significant in preventing outbreaks which are both naturally occurring or the result of bioterrorist activity. Ebola and Marburg viruses have been identified as the cause of several highly lethal outbreaks of hemorrhagic fever for which there is no effective treatment or cure. Therefore, vaccine studies are critically important for protection against infection. We developed a highly effective vaccine strategy for Ebola virus infection in non-human primates. The vaccine yielded 100% protective efficacy against Ebola infection and showed for the first time that protective immune responses could be generated in primates. The vaccine is currently being tested in Phase I human clinical trials conducted by the VRC Clinical Trials Core Laboratory. We have applied a similar strategy to the development of protective vaccines against Marburg virus.